Merge pull request #21995 from rmohta/issue-21803

Add a note about reserved namespace prefix. Resolves #21803

content/en/docs/concepts/overview/working-with-objects/namespaces.md

@@ -43,6 +43,10 @@ resources within the same namespace.
 Creation and deletion of namespaces are described in the [Admin Guide documentation
 for namespaces](/docs/admin/namespaces).
 
+{{< note >}}
+    Avoid creating namespace with prefix `kube-`, since it is reserved for Kubernetes system namespaces.
+{{< /note >}}
+
 ### Viewing namespaces
 
 You can list the current namespaces in a cluster using:

content/en/docs/tasks/administer-cluster/namespaces.md

@@ -82,6 +82,10 @@ See the [design doc](https://git.k8s.io/community/contributors/design-proposals/
 
 ## Creating a new namespace
 
+{{< note >}}
+    Avoid creating namespace with prefix `kube-`, since it is reserved for Kubernetes system namespaces.
+{{< /note >}}
+
 1. Create a new YAML file called `my-namespace.yaml` with the contents:
 
     ```yaml